Self-contained electrostatic air cleaner



Sept. 10,1940. T- a R; 1.. H! LDEBRAND 2,214,535

SELF-CONTAINED ELECTROSTATIC AIR CLEANER Filed April 15, 1938 Z sheetsgiew Fig,

W'TNE55E;55 Q INVENTOR y We v v v I /?0/,0h L. H/Mabmnd ATTORNEY" Sept. 10,1940. R H|| DE BRAND 2,214,585

SELF-CONTAINED ELECTROSTATIC AIR CLEANER Filed April 15, 1938 2 Sheets-Sheet '2.

WITNESSES: INVENTOR ATTORNEY Patented Se t. 10, 1940 sELr coN'rmNEn"nmc'mos'ra'rloara CLEANER I ma. r. Hildebrand,jPlttsburgh,Pa;'assignor to Westinghouse Electric & Manufacturing (Lompany, East Pittsburgh, Pa.,

Pennsylvania a" corporation of l Application Apr-1115,1938,.serialNo.202,233 50mins. (01.133 7) This invention relates generally to a fan unit comprising an'air blower or propeller and driving'means therefor andwhich finds special application in portable and semi-portable aircohditionin'gunits with many: attendant advantages. I f 3 1; I

Ina unit of this character, and particularly household room units, air 'isdrawn in .an air inletopening in the unit and exhausted through arifoutlet-opening; usually by means of'axfan. In the course of this journey,;the air is conditioned-in accordance with' the particular char-@ acteristics of the unit. whichmaybe, as'in the w I is a high resistance'rotor. This lightened load instant disclosure, an air cleaner unit thatv rell moves ioreignparticles, such as dust.

In household units andythe' like,-it is/some times desirable to have two diii'erent rates of air flow throughthe unit, one for general use and the-other for special or-exceptional use.

35 when the air being cleaned is-recirculate'd', that is, air which has previously passed throughthe cleaner and is drawn back into the cleanerg from the room, and'the second rate may be preferred of acommon type singledirection motor driving 36 thefan blower propeller. Either scheme has objections which in the interests of economyand veaseoi control maybe-deemed serious. I propose to obtain two diflerent rates of air flow by a 'm'eans which I- believe .to be entirely new. 4o Brieily," I employ a fan; blower havingtwo dif- Ierent'outputs depending upon its direction'of rotatii'm, and by driving the propeller by a re-' versible motor controlled'byj a single 5 switch, a selection of the two rates, can be easily and readilyf obtainedj Inasmuch as most households I I have jsingle-phase service, the choice of the'more common types of motors is extremely limited for reasons of economy. ,However, by utilizing a capacitor run motor and by connecting the ca-' -pacitance to the one or theotherwindings or I circuits thereof, I providea motor adaptable tov my purpose. In fact, many of the characteristics of the capacitor motor harmonize so completely 55 with the characteristics oi the Ian blower I have I Thus, 90 for example, it the unit'is an air cleaner or an electrical precipitator, a low rate of air flow may r be's'ufilcient for most purposes, but when a large number of persons congregate ahigher rate may, be desired. or again, one rate may be desired comprising the inletto the fan blower.

chosenthat an idealcombination forithe urpose is obtained having'many advantages.

' oneadvantage of my combination Ian unit is the tendency to yield a constant volume of air flow throughthe unit for a given rotation of the 5 t same, As is well known, a centrifugal blower oi a squirrel-cage type with'angular or curved blades has .a tendency to reduce its volume oi discharge with an increase of air resistance, and this,;of course, lightens the load on the motor. 10 However,the capacitor motor, on' the other hand has a tendency to increase its speed with the reduction; of fits load particularly'when the rotor,

on the motorwill, therefore, tend to increase the 16 speed of rotation of the motor and fan, bringing the volume up again so that the 'overallcombination is one that seeksto maintain a constant volumeof-airflow. Y

A second advantage that I'obtain is the ease ,20

with which :Ican reverse the direction of rotation. By connectingcthe elements of the capacitor motor to the single-phase supply line, 'I can with only a simple switch select the direction in whichthe motor and fan is to rotate, and,'ii de- 25. sired, I can also incorporate into the switch a position which will render the motor and fan inactive 1 In the operation of an electric'precipitator designed forhousehold use, noise mustbe minimized in ordergfor the-unit to be commercially acceptable, andit is' a further feature of my invention to so associate the parts of ,such anair" cleaninghdevicei that quiet, operation results. Moreover, thepartsare associated so that, dust is .notdeposited on them except, of lcourse, in thecell where itis desired to collect, the dust. Thus the interior of the unitis maintainedclean even with long continued use.

' It is, oi'course, more or less, essential for a 40 household unit" of the. type being'd'escribed to be quiet in its'operatio'n. To, incorporate this quietness in my unit without sacrificing the above and other advantages oi my invention, 1" add a'shroud tort'h'e, blower which follows the contour of. the aperture in a wall of the unit I I Furtheradvantages and features or my invention will be apparent irom the following description of an. embodiment thereof, in the drawings of which:

- Figure 1. is a view of an electrical precipitator with the back panel removed, and generally showing an internal assembly view oi the main parts thereof;

ENT F- C T. I

ment,-or airmayj be drawn from an inlet (not Fig. 2 is a side view ofrny motor and fan; Fig. 3 is an end view of the fan; and

Fig. 4 is a symbolic diagram showing the connections to a capacitor motor adapted to my invention. I p a Referring more specifically to Fig. 1, I have right-hand compartment is furtherdivided by a horizontal air filter 3. The partition 2 has a circular aperture 4 therein which serves as the means by which air may be drawn from the right-hand compartment by a fan indicated in its entirety by the numeral 5.

Generally, an air cleaner of the type disclosed operates upon the following principles. Air may be drawn from an air inlet (not shown) in the top of the cabinet over the left-hand compartshown) at "the back'end of the cabinetat the upper portion of the left-hand compartment. A

. damper 6, 'whose position is controlled by a knob I, determines which of these inlets is the source of supplyfor air to the unit. The inlet at the I top of the unit is usually opened to the premises in which the cleaned airis discharged, while the inlet'in the back or the shown) leadingto a fresh air supply. By means of the knob l, I cancontrol the position of the damper 6 which a fresh air and recirculated'air that is desired to be passed through theuriit:v The air is drawn into theunit by the i of these inlets and passes into-an ionizing and dust. collecting cell 8, from whence it passes to the fan bloweror propeller I0 and is forced up- I the right-hand compartment through the filter ward through 3and an outlet opening (not shown) in the top of the The filter 3- is primarily the electrical apparatus below it, and'which in-' cludes .thehigh-voltage power pack ll for-supplying thenecessary high voltages to the vcell 8.

The ionizing andcollecting c'ellf8 may be com structed in any approved, manner, as, for 'example, in accordance with left-hand compartment and discharged into the unit may be adjacent an 1 open window or a discharge for a conduit (not In this figure,.the windings '20 and 2| are symi bolic of the induction-windings will give any relative ratio of fanji'through either or both cabinet above the rightthe teachings of Pate ent No. 2,129,783, of G..W. Penney, granted Sep--' tember 13, 1938, and assigned to the Westinghouse Electric & Manufacturing Company. It should be noted that the flow of the'air through rthe unit is such that the air to be cleaned passes through the cleaning cell 8 almost immediately after being drawn into the cabinet."

After this, only cleaned air means 1 l. V 7

Referring more particularly to Figs. 2, 3 and 4, the fan 5 comprises a symmetrical, reversible capacitor motor l2 driving a centrifugal blower 13 similar in construction to a squirrel cage."

Thisblower comprises an end plate l4 and an annular end ring l5 between which are secured blades Hi. In assembling the fan in theunit, the ring [5 is juxtaposed as close as possible to the surface "of the partition 2, the aperture 4 of which is slightly greater than the internal diameter of the ring 15. I

Extending from the ring I5 is a shroud l8 of a diameter very slightly less than the aperture envelops the restof the parts of the precipitator unit such as, for example, the blower and the power pack rectifier- 2| is a. condenser 4 and extending substantially to the surface IQ of the partition 2. By this construction I introtially eliminates the turbulence of the air flowing into or around theblower and which I have household units of the character described.

The propeller may be constructed in any manner desired, but I have found that a very satisfactory blower can be made by casting the'same in its entirety. blades 16 are at an "angle to a radius drawn to It may be observed that the either end thereof. Whenthis fan blower is rotated in one direction, that is, with the blades curved or extending backward, one volume of air is. obtained, but when the propeller is rotated in a reverse direction at substantially the same and lesser-volume is obtained.

speed, a second of approximately 250 cubic feet per minute was I was obtained against the: same air pressure re-' striction; I

I provide a simple man nerotcontrollingthe rotation of the motor whichis shown in Fig. 4.

motor and are electrically spaced therein. This spacing, of course, is in accordance with the usual design principles and is preferably although ment the power delivered .ineither direction is substantially the same as is the speedof rotation although it is obvious that'I may make the power greater in the ,directionfor greatest output of the fan and lesser in the opposite direction. One end of each winding andthe power lead found to be an annoying source of sound in I dischargedwhen the fan was-run with the blades backwardly curved, and inthe reverse direction of rotationa volume of cubicv feet per minute of the capacitor.

351* 1 I do not desireto :be limited theretog. Moreover, v,

23 are, conductively connected together as represented by terminal 24. Of the windings symbolicallyindicated atZOand circuits being firstly, ly, the

Across the other ends 25-. Leads 26 .andZI conduc-f 'tively extend from the'junction points of the two sides. of the condenser to two poles 28 and 3 30 of a switch 3| having a movable blade or other circuit controlling means 32, the fixed terminal, of which isconnected tothe other powerlead 33.

If now the blade'32 isplaced upon the terminal or pole 28, Wis obvious that the winding 2B.be-. 7 comes the main winding and, the winding 2L By placing the switch blade 32 upon the terminal" I of pole 30,. the winding 2l becomes the main.

winding, and. the auxiliary circuitiscomprised in whichthe power conductor 33 is disconnected from the motor and this is symbolically 'indi-*' 70 cated by the vertical position of the circuit controlling member 32.

sired volume 6 l of the winding20 .and condenser 25 in series. If desired, the switch 3| :nriay have a third position. r

20 Thus with the motor of the type describedand the fan substantially asthat shown, a volume.

. so; the winding 20, and secondwinding 2I in series with co'ndenserl25 gfl Y L 2,214,585 I throwing the switch from one pole-to the other.

No" additional speed and direction controlling appurtenances are required, as would be necessary with other types of single phase motors adaptable for operation in the customary household supplied only with single-phase power Moreover after trying many variations I have found the operation of the described household precipitator unit 1 to be exceptionally quiet, regardless of the direc- I tionof rotation of the motor, when the disk l5 and shroud 18 are close to. the partition; and the shroud l8 extends substantially to the surface IQ of the partition.

While I have described my fan unitapplied to an air cleaner essentially of the self-contained household type, it'is apparent thatI'am not limited'thereto. It is obvious that many changes maybe made within the spirit and. scope of the invention described. ,It is desired, therefore, that the appended claims be given the" broadest construction consistent with their limited only by the prior art.

Iclaim as my invention; 1 1

a partition in said cabinet having a circular aperture near the bottom thereof, said partition creating two zones in said cabinet for the passage of air, a centrifugal blower, having annular I disks and air-propelling blades therebetween, a

shroud connected to the inner periphery of one of saiddisks, a motor mounted in one of. said zones and having a shaft to which said blower is secured with the last said vdisk very close to one surface of said pa tition, and said shroud extending within said aperture, and terminating substantially at the other surface of said part1} tion, said shroud being" of" external diameter slightly less than that of the said aperture whereby quiet operation results. i 2. The structure of claim 1 is areversible capacitor motor;

3. An electrical precipitator for household use comprising, a cabinet, a partition in said cabinet having a circular aperture near the bottom thereof, said partition creating two passage zones in said cabinet for the passage of air, said cabinet having an air intake opening at the top of one of said zones, and anair outlet opening at the wherein the motor top of the other of said zones, an electrical aircleaning cell disposed in one of said zones intermediate said intake openingandsaid aperture, a centrifugal blower for drawing air into said one zone through said intake opening, through said cell, and finally discharging the air out through I 'said' outlet opening, said blower being disposed below *said cell, said blower comprising annular discs and air-propelling blades therebetween, a shroud connected to the inner periphery of one of said discs, a motor mounted in one of said zones and having a shaft to whichsaid blower 'is secured with the last said disc very close to ing disposed below language I and one surface of said partition, and said shroud extending within said aperture, and terminating substantially at the other side of said partition, said shroud being of external diameter slightly less than that of the said aperture whereby quiet operation results. q

4. An electrical precipitator for household use comprising, a cabinet, a partition insaid cabinet having la circular aperture near the bottom thereof, said partition creating two passage zones in said cabinet for the passage of air, said cabinet having an air intake opening at the top of one of said zones, and an air outletvopening at the top of the other of said-zones, an electrical air-cleaning-cell disposed in one of said zones intermediate said intake opening and said aperture, a centrifugal blower for-drawing air into said one zone through said intake, opening,

, through said cell, and finally discharging the air out through said outlet opening, said blower beaid cell, said blower comprising annular discs and air-propelling blades therebetween, a shroud connected tothe inner periphery of one of said discs,"a motor mounted in one ofsaid zones and having a shaft to which i 1 said blower is secured with the last said disc 1. In a device of the class described, a'cabinet,

very close to one surface of said partition, said shroud being of an external diameter slightly comprising a cabinet, a partition in said cabinet having a circular aperture near the bottom thereof, said partition creating two passage zones in said cabinet for the passageof air, said cabinet having an air intake opening at the top of one of saidzones, and an air outlet opening at the top of the other of said zones, an electrical aircleaning cell disposed in one of said zones intermediate said intake opening and said aperture,

a centrifugal blower for drawing air into said one zone through said intake opening, through said cell, and finally. discharging the air out through said outlet opening, disposed below said cell, said blower comprising annular discs and air-propelling blades therebetween, a shroud connected to the inner periphery of one of said discs, a motor mounted in one of said zones and having a shaft to which said blower is secured with the last said disc very close to onesurface of. said partition, said shroud of an external'diameter slightly less than that of the portion ofithe surface of said partition said blower being which defines said aperture, whereby quiet operation of said precipitator results, the said blades being disposed at an angle to the radii in the I same plane from the center of said discs, whereby being reversible. RALPH L. 

